#17000: how to use SetMorphism?
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Reporter: elixyre | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.4
Component: categories | Keywords: morphism
Merged in: | Authors: Jean-Baptiste Priez
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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Hello every one,
I want create set bijections in sage...
{{{
sage: U = Set({'a', 'b', 'c', 'd'})
sage: V = Set({1,2,3,4})
sage: from sage.categories.morphism import SetMorphism
sage: bij = SetMorphism(
....: Hom(U, V, Sets()),
....: lambda l: {'a':1, 'b':2, 'c':3, 'd':4}[l]
....: )
sage: bij('a')
---------------------------------------------------------------------------
TypeError Traceback (most recent call
last)
<ipython-input-4-c2a304e84b3a> in <module>()
----> 1 bij('a')
/Users/elix/sage/newinst/cha/local/lib/python2.7/site-
packages/sage/categories/map.so in sage.categories.map.Map.__call__
(sage/categories/map.c:5346)()
TypeError: a fails to convert into the map's domain {'a', 'c', 'b', 'd'},
but a `pushforward` method is not properly implemented
}}}
How to do this.?
--
Ticket URL: <http://trac.sagemath.org/ticket/17000>
Sage <http://www.sagemath.org>
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